Froth flotation of acidic minerals



- organic solvents.

Patented Aug. 29 1944 2,356,821 FROTH FLOT'ATION 0F ACIDIC MINERALS Ludwig Jacob Christmann, Yonkers, N. Y., David Walker Jayne, Jr., Old Greenwich, and Stephen E. Erickson, Springdale, Conn., assignors to American Cyanamid Company, New York, N. Y., a coporation of Maine No Drawing. Application September 4, 1940,

Serial No. 355,368

2 Claims.

The present invention relates to mineral concentration. More particularly it relates to a new class of. reagents for selectively separating acidic minerals from ore materials,

This application is in part a continuation of our application Serial No. 326,952, filed March 30,

1940, patented March 31, 1942, Patent No. 2,278,-

In accordance with this invention natural ores or artificial materials comprising mixtures of acidic minerals with other mineral constituents are subjected to a separation or concentration process in the presence of a promoter, said promoter being a member of the class-of condensation products obtained by reacting one molecular equivalent of a polyalkylene polyamine with one molecular equivalent of a fatty acid or fatty acid ester, and the salts of such products, to effect a separation of the acidic minerals from the other ore constituents. Particularly this invention relates to the use of the monoacidyl reaction prod- .ucts of polyalkylene polyamines with fatty acids,

fatty acid glycerides or other esters, either as the free base or as the substantially water-soluble salts of such products as promoters or collectors for acidic minerals in froth flotation, film flotation, Stratification, agglomeration, tabling, and related mineral separation processes. While the invention is not limited to any particular ore concentrating process or to any particular ore, its most important field of usefulness is in connection with the froth flotation processes of separating silica or silicate minerals, such as mica, from non-metallic ores, such as limestone, bauxite, barytes, ilmenite, calcite and the like, and especially phosphate minerals.

The compounds that have been found to have a selective filming attraction for acidic minerals and useful for carrying out the present invention include broadly the mono-acidyl reaction products of polyalkylene polyamines with fatty acids,

fatty glycerides or other esters, and salts of these reaction products. These compounds are, in general, surface active and are basic in character. A general method of preparing the above reagents comprises heating one molecular equivalent of a fatty acid, or an amount of fatty acid glyceride sufiicient to yield the equivalent of 1 mol of the fatty acid, with one molecular equivalent of a polyalkylene polyamine at a temperature of about 230-240 C. until the reaction is complete. The products are usually'homogeneous viscous pastes which are soluble in aliphatic alcohols or other They combine with acids such as formic, acetic, hydrochloric, and the like to yield salts which are soluble in water. These mono-acyl derivatives of the polyalkylene polytion that relatively crude mixtures of the various amines are those most probably represented by the following general formula:

YCONH-A-- Z in which A represents the group j CHR-CHR'NH- or two or more such groups serially arranged, R and R may be hydrogen or alkyl radicals, Y stands for an aliphatic hydrocarbon radical containing at least nine carbon atoms which hydrocarbon radical may contain one or more double bonds and may be substituted by hydroxy groups, Z stands for hydrogen, and salts of such compounds.

Representative polyalkylene polyamines which may be employed in condensing with the fatty acids are diethylene triamine, dipropylene triamine, dibutylene triamine, trlethylene tetramine, tetraethylene pentamine, or mixtures of any two or more of such polyamines either as relatively pure compounds or crude mixtures. In general they are polyamines thediiferent amino groups of which are separated from one another by a hydrocarbon radical containing from 2 to 12 carbon atoms. It is an advantage of the present invenpolyamines may be used for reacting with the fatty acids or fatty acid glycerides which results in the production of reagents at a lower cost than possible by using the purified polyamines. For

example, when based on the saponification value of coconut oil and the average molecular weight of a crude'mixture of polyethylene polyamines, a ratio of approximately 35 parts of amine to 60 parts of oil will yield a product consisting essentially of mono-acyl derivatives. The product so produced is suitable for use as a silica promoter and it is not necessary to remove the glycerine split off by the reaction.

Either the saturated, unsaturated, hydroxy fatty acids, or glycerides having at least 9 carbon atoms, may be employed for reacting with the polyamines. Representative acids and fatty acid glycerides include lauric, palmitic, stearic, oleic, ricinoleic,'capric', and myristic, mixtures of such acids or glycerides'and especially mixtures of the fatty acids or glycerides found in the fats and oils of either vegetable or animal sources, such as those in coconut oil, palm kernel oil, cottonseed oil, corn oil, linseed oil, olive oil, peanut oil, fish oils, and the like.

The promoter action of the reagents of the present invention will, of course, vary with' different acidic ore minerals and with the different polyalkylene polyamine fatty acid condensation products or salts used. For-example, with the'monoacyl polyalkylene polyamines produced from fatty acid glycerides in which the average molecular weight of the fatty acids is comparatively low,

such as those of coconut oil and palm kernel oil;

the bestresults are obtained when such compounds are used in the form of their water-soluble acid addition salts, for example, the acetates.- When the mono-acyl polyalkylene polyamine is produced from fatty acid glycerides, the average molecular weight of the fatty acids of which is relatively high, such as those of cottonseed oil, they give the best results when used in the form of the free base. Therefore, it is not necessary to the present invention to use water-soluble salts, and the compounds in the form of the free base may be used provided satisfactory dispersion and distribution is effected. In the froth flotation separations, dispersion may be effectively obtained by feeding an alcoholic solution of the compound into the flotation circuit or by the use of emulsions containing the reagents dispersed therein.

The reagents of the present invention are effective promoters or collecting agents for acidic ore materials generally and said acidic materials may be either worthless gangue or valuable ore constituents. The most important use, however, is in connection with the froth flotation of silica from non-metallic ores in which the silicious ganguemay represent a much smaller proportion of the ore rather than metallic sulfide ores in which the gangue usually represents the major proportion of the ore. Representative acidic ore materials are the feldspars, quartz, pyroxenes, the spinels, biotite, muscovite, clays, and the like.

While as stated heretofore the present invenvantage of this invention that our reagents not.

only effect satisfactory removal of the silica but are economical in ,amounts used. The quantities required range from 0.1 pound to 2.0 pounds per ton of ore depending upon the particular ore and the particular reagents. The invention is not, however, limited to the use of such quantities.

These reagents have also been successfully used for the flotation of feldspar from quartz and for the flotation of mica from quartz and calcite.

The reagents of the present invention may be used alone or in mixtures with other promoters. They may likewise be used in conjunction with other cooperating materials such as conditioning reagents, activators, frothing reagents, depressing reagents, dispersing reagents, oily materials such as hydrocarbon oils, fatty acids or fatty acid esters.

These new reagents are also adaptable for use in any of the ordinary concentrating processes such as film flotation, tabling, and particularly in froth flotation operations. The ore concentrating processes employed will depend upon the particular type or kind of ore which is being processed. For example, in connection with phosphate rock, relatively coarse, phosphate bearing material, for example 28 mesh and larger, canbe economically concentrated by using these reagents in conjunction with other materials such as fuel oil or pine oil and subjecting to concentration by the use of tables or by film flotation.

The 28 mesh phosphate rock material is best concentrated by means of froth flotation employing these improved silica promoters.

When the reagents of the present invention are employed as promoters in the frothflotation of silica from phosphate rock, the conditions may be varied in accordance with procedures known to those skilled in the art. The reagent may be, employed in the form of aqueous solutions, emulsions, mixtures, or solutions in organic solvents such as alcohol and the like. The reagents may be introduced into the-ore pulp in the flotation cell without prior conditioning or they may be conditioned with the ore pulp prior to the actual concentration operation. They may also be stage .fed into the flotation circuit.

Other improved phosphate flotation features hindered settling classifier and which deslimed feed is well suited for treatment in accordance with this invention.

The invention will be further illustrated by the following specific examples which are illustrations of the preferred embodiments thereof, but it is not intended to limit the invention thereby.

- EXAMPLE 1 Flotation-tests as follows were made on a sample of Florida phosphate ore from the Old Colony mine near Brewster. This ore material which was essentially 48 200 mesh material was agitated and scrubbed with water to break ,up the clay balls. The slimes were subsequently removed by decantation and washing repeated until the ore material was substantially free of slimes.

Separate 600 gram samplesof the deslimed flotation .feed were diluted to 20% solids with water and transferred to a laboratory size Fagergren flotation machine. The particular reagent or reagent combination was added to the pulp. The machine was started up and the pulp and reagent mixed for five seconds. admitted to the machine and the resulting concentrate was skimmed off for three minutes. The flotation testproducts were then filtered, dried, weighed and assayed. The metallurgical data obtained in these tests are presented in Table I.

Table I Tailing (ghosphate T t R t M 1 pm uct) es eagen ono-acy No. reaction product oi- Promoter Weight Insol.

Lba/to'n Percent Percent l Diethylene trlamine and 1.0 39. 11 0.80

coconut oil (acetate). 2 Diethylene triamine and 1.0 38. 38 6. 40

myristic acid (acetate). 3 Mixed polyethylene poly- 1. 0 34. 63 3. 24

amines and coconut oil (acetate). 4; Mixed polyethylene polyl. 0 34. 50 3. 32

amines and coconut oil (acct 5 Mixed polyethylene poly- 0. 5 31. 66 2. 64

amines and coconut oil.

Air was then EXAMPLE4 Another series of tests was run on a difiefinix TEST A SAMPLE RAKE SANDS FROM THE TAKING sample of phosphate rock from the Old Colony mine; The original sample used in these tests contained less slime than the sample used for the preceding tests. The testing procedures, scrub bing," desliming and flotation, used for this series of tests was the same as that followed in the previous tests. The metallurgical data obtained in these tests are found in Table II.

Pnopucsn BY THE VALLEY FORGE CEMENT Commmr The tailing produced at the Valley Forge Cement Company plant is sent to a rake classifier. The'rake classifier sands are treatedeby flotation to remove part of the alumina which is "present in the form' of mica. desired, The rake sands were composed of cal- Table II Telling (phosphate Test product) No Reagent: mono-acyl reaction product oi Promoter Frother Weight 111801.

. Lba./to'n Lin/ton Percent Percent Mixed polyethylene polyamines and coc0nut.0il (acetate) v 0.90 0. 16 37. 3. .do 1.00 0.10 30.33 3.08 Mixed polyethylene polyamines and fish oil (acetate) 0.70 0. 16 45.14 6.28 Mixed polyethylene polyamines and palm kernel oil (acetate) 0.60 l 0. 16 34. 87 3. 36 "Mao 0.70 0. 10 32.73 3.20 Mixed polyethylene polyamines and cottonseed oil (acetate) 0. 50 l 0,16 40. 70 6. 28 d 0.00 0.10 30.20 4.84 0.00 1 1.07 30. 21 2. 50 0. 90' 1 1. 40. 25 2. 02 0.70 0. 03 43. 70 4.20

1 Pine oil. ,Higheralcohol omen cite, mica, quartz, and pyrite. Analyses are given below. EXAMPLE 3 Another-series of tests was run on a different Analysis ofrake sands igig g sample of phosphate rock from the Old Colony mine. The testing procedure, scrubbing, de- Mesh Percent sliming, and flotation used for this series of tests (Tyler) weight was the same as that followed in ,the previous tests. The metallurgical data obtained in these 48.66 +05 1.00 tests are found in Table III. The results of the $33 fig; 312 flotation tests shown in the table are the aver- 37.63 200 25.27 ages of at least two duplication flotation tests, ii? 23:32

the results of which check within the limits of reasonable experimental error.

Table III T n h h solids with tap water.

a ing osp ate Test Mono-acyl reagentz' reaction prodpm net) 1.0 lb. Of AICIILGHZO per ton 0 f rake sands was net of polyethylene polyamlnes added to the charge and conditioned with the and- Weight Insol, P p for 1 minute. Then 0.15 lb. of the acetate of the mono-acyl reaction product of mixed poly- C 1 g ethylene polyamines and coconut oil and 0.057

0m 01 .4 3.08 Peanutofl 35.43 M0 lb. of a higher alcohol frother per ton of rake Cottonseed n. 35.54 2.03 sands were added. The resultmg concentrate ig g been was skimmed off for three minutes. The results Linseedoil: 3911s 3112 of h s s are given l w: Herring oil 36. 38 3. 60 Oleic acid. 40.03 5.15 Table IV Palm kernel 01] 43:99 6. 97 Coconutoil 44.79 11.11

Acetate of reaction product used in 39. 33 5. 51 Distribution te t 9 Percent Percent Percent Acetate of reaction product used in 40. 30 6. 30 Weight A120: S102 test 10. A1203 s10,

1 All reagents. except in tests 9A and 10A, used as the free base and C0ncentmte 28 10 41 89 70 25 73 e a e g g mixture p z g g gangs??? Telling 70.72 4. 33 30. 50.30 74:27 C81 0D BtOl'l'lS. lOll promo 61.Wi 011 0 e 00 0 F v 1 Reagents in tests 9A and 10A used as aqueous solutions, 0.6 lb./ton eed 00 6 60 91 100 00 100'00 with 0.8 lb./t0n mixture of aliphatic alcohols having 7-10 carbon EXAMPLE 5 atoms.

An analysi of the metallurgical data found in FLOTATION 0F SILICA FROM AN IRON ORE Tables I, II and III showthat in most tests the 5 A sample of magnetic separation plant tailphosphate product (tails) is of a satisfactory marketable grade. In many of the tests (those in which the assay is less than 5% insoluble) the phosphat product is of a better grade than is currently produced by the flotation of phosphate particles from the quartz.

In most of the tests the weight recovery of the phosphate product is much higher. than would be obtained in the soap flotation of the particles.

A charge of this material containing 600 grams of dry solids was placed in a laboratory size Fagergren flotation machine and diluted to 22% ings was used in these tests. The screen analysis of this material is given below:

Percent Mesh (Tyler) weight The removal of silica is not sisted of magnetite, limonite and quartz. Flotation of the iron minerals away from the quartz resulted in the recovery of the magnetite in :1

low grade concentrate. The limonite was not floated, however.

A teston the flotation of the silica from the iron minerals was conducted, using a charge of the tailing deslimed at approximately 1000 mesh in respect to the settling rate of quartz. The deslimed material was placed in a Fagergren flotation machine and diluted with tap water. 0.50 lb. of the acetate of the mono-acyl reaction product of mixed polyethylene polyamines and coconut oil and 0.057 lb. of a higher alcohol frother per ton of tailing were then added and conditioned with the pulp for 3 seconds. Air was admitted and the resulting rougher concentrate was skimmed off for 2 minutes. This rougher concentrate was cleaned by refloating. The results of this. test are given below:

Percent Percent Dist. percent weight Fe Fe Slime 43 7. 66 Clean concentrate 11. 38 19.38 Clean tail 22. 86 29. 33 Rough tail 48. 67 43. 63 Feed A 22. 46 100.

The rougher tailing resulting from the flotation of the silica contained both magnetite and liihonite and assayed nearly twice as high in iron as any concentrate that was produced by conventional soap flotation of the iron minerals.

We claim: 1. In the froth flotation process of separating phosphate ore values from acidic siliceous gangue the step which comprises subjecting the ore to in which n, m,' and a: are small whole numbers, with coconut oil, and salts thereof.

2. In the froth flotation process of separating phosphate ore values from acidic siliceous gangue the step which comprises subjecting the ore to froth flotation in the presence of a reagent pro-.

duced by reacting coconut oil with a mixture of polyethylene polyamines represented by the following general formula:

in which a: is a small whole number in a proportion such that the mono-acyl polyethylene polyamin derivative is produced, and salts thereof.

LU'DWIG JACOB CI-IRIS'IMANN. DAVID WALKER JAYNE, JR. STEPHEN E. ERICKSON. 

